# transparency on image rendered as polygon

**URL:** <https://community.cesium.com/t/transparency-on-image-rendered-as-polygon/3039>\
**Category:** CesiumJS\
**Created:** [September 9, 2015, 7:51am UTC](https://community.cesium.com/t/transparency-on-image-rendered-as-polygon/3039 "2015-09-09T07:51:54Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![neelredd](https://avatars.discourse-cdn.com/v4/letter/n/9de053/32.png) [@neelredd](https://community.cesium.com/u/neelredd)\
**Post date:** [September 9, 2015, 7:51am UTC](https://community.cesium.com/t/transparency-on-image-rendered-as-polygon/3039/1 "2015-09-09T07:51:54Z")

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Hello All,

Just wanted to know whether cesium supports transparency/alpha for groundOverlay/image

the sample czml for the same is as given below using ImageMaterialProperty : please let me know whether alpha can be applied on image.

"polygon":{  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"positions":{  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"cartographicDegrees":[  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;-122.38607211584785,37.79088473344126,0,-122.38607211584785,37.789267771712346,0,-122.38768907757675,37.789267771712346,0,-122.38768907757675,37.79088473344126,0,-122.38607211584785,37.79088473344126,0  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;]  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;},  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"show":true,  
&nbsp;&nbsp;&nbsp;&nbsp;"material":{  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"image":{  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"image":"images/add.png"  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;}  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;},  
&nbsp;&nbsp;&nbsp;&nbsp;  
&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;"fill":true  
}

thanks,  
neel

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<div class="post-metadata">

**Author:** ![hannah](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/hannah/32/4509_2.png) [@hannah](https://community.cesium.com/u/hannah)\
**Post date:** [September 10, 2015, 3:46pm UTC](https://community.cesium.com/t/transparency-on-image-rendered-as-polygon/3039/2 "2015-09-10T15:46:59Z")

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Hello Neel,

Currently, there isn’t a way to configure the transparency on an image material. We have this issue on GitHub to fix that:[https://github.com/AnalyticalGraphicsInc/cesium/issues/2484](https://github.com/AnalyticalGraphicsInc/cesium/issues/2484)

Most other materials can be made transparent using the alpha value in color.rgba.

Best,

Hannah

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**Author:** ![Thinh\_Ho](https://avatars.discourse-cdn.com/v4/letter/t/22d042/32.png) [@Thinh\_Ho](https://community.cesium.com/u/Thinh_Ho)\
**Post date:** [February 17, 2016, 3:28pm UTC](https://community.cesium.com/t/transparency-on-image-rendered-as-polygon/3039/3 "2016-02-17T15:28:32Z")

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We mitigated this issue in our application at our service that streams CZML. The actual image is modified in java and sent across the wire already rendered with a specified alpha value.

We ran into an issue where we would see, for a split second, the white background before the image is loaded onto the polygon. Is there is way to specify an initial no fill or transparent polygon?

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<div class="post-metadata">

**Author:** ![Scott\_Hunter](https://sea2.discourse-cdn.com/cesium/user_avatar/community.cesium.com/scott_hunter/32/2006_2.png) [@Scott\_Hunter](https://community.cesium.com/u/Scott_Hunter)\
**Post date:** [February 17, 2016, 3:32pm UTC](https://community.cesium.com/t/transparency-on-image-rendered-as-polygon/3039/4 "2016-02-17T15:32:17Z")

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This is a long-standing bug in Cesium.

See [https://github.com/AnalyticalGraphicsInc/cesium/issues/1640](https://github.com/AnalyticalGraphicsInc/cesium/issues/1640) for more details.